Mouse support seems like the best feature for me as well for this release. got a microsoft surface mobile mouse to work instantly with iPad on iOS 13. Txt selection works, however you have to double click the txt, and hold and drag after the second click. Works wonderfully if you get used to the double click to drag, select. Then select and cut options pop up, which you can click on instead of right click. It’s really quite nice. As a bonus, the scroll wheel on my mouse works! only problem is doesn’t have natural scroll. Old style scrolling, i.e. scroll up to go up. Really has become nearly a laptop for me so far. The big wheel cursor is annoying but I have gotten used to it within a few hours after having iOS 13 installed.